chore: sync version to 0.1.21 (already published to PyPI)

Version 0.1.21 was successfully published to PyPI but the version bump
commit failed due to branch protection. This commit syncs the repo version
with what's already on PyPI.

Author: jon-myers

idtap/__init__.py

@@ -1,6 +1,6 @@
 """Python API package exposing IDTAP data classes and client."""
 
-__version__ = "0.1.20"
+__version__ = "0.1.21"
 
 from .client import SwaraClient
 from .auth import login_google

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "idtap"
-version = "0.1.20"
+version = "0.1.21"
 description = "Python client library for IDTAP - Interactive Digital Transcription and Analysis Platform for Hindustani music"
 readme = "README.md"
 license = {text = "MIT"}